The High‐Temperature Oxidation Behavior of a HfB2 + 20 v / o SiC Composite

The high‐temperature oxidation behavior of a composite was investigated in the temperature range 1200°–1550°C and in oxygen partial pressures at 1400°C ranging from . Oxidation kinetics in pure oxygen were parabolic, with the rate constants exhibiting linear Arrhenius behavior. The rate of oxygen consumption is described by in the range 1350°–1550°C. The oxide scale formed in this range consisted of an inner layer in series with an outer layer. The oxidation rate was found to be controlled by initial short‐circuit oxygen diffusion through the , followed by volume diffusion through the scaling layer. Below 1350°C, rapid oxidation kinetics were observed, being the primary scale constituent.